1. Field of the Invention
This invention relates to a capsule for use in preparing a dental amalgam, and more particularly, to such a capsule which may be opened to inspect the contents following amalgamation, and, if necessary, securely resealed for further amalgamation.
2. Description of the Related Art
In the field of dentistry, dental professionals use capsule systems in order to prepare dental amalgams for use in filling patients"" cavities.
Such capsule systems typically include a body portion and a removable cap portion which combine to form a mixing chamber. Such capsule systems further include an amalgam alloy and mercury, with the mercury being kept separate from the alloy until the dental professional is ready to form the particular amalgam.
In one particular system, a mercury-containing bag or pouch is placed in the chamber body, along with the particular dental amalgam alloy. The chamber body and chamber cap then are welded together, or bonded together using a suitable adhesive or other bonding material. At this point, the particular capsule is placed in an amalgamator, also known as a vibration mixer, which moves the capsule backward and forward at extremely high speeds, generally in a direction which is along the longitudinal axis of the capsule system.
During the amalgamation process, extraordinarily high acceleration forces are exerted on the contents of the capsule. The mercury-containing bag or pouch is designed to rupture or burst due to the reversing forces of the amalgamator.
Once the amalgamator has shaken the capsule system, at a particular frequency for a particular length of time, the dental professional then breaks the seal on the capsule system in order to gain access to the contents of the mixing chamber. Typically, the dental professional breaks the seal by inserting one end of a cylindrical rod into a corresponding cylindrical socket formed on the top of the cap portion. Then, by using the cylindrical rod as a lever, the professional may break the cap portion away from the body portion, and subsequently empty the contents of the mixing chamber into a dental amalgam basin. However, this breaking process is awkward, and may cause accidental spilling of the contents.
Because the body portion and cap portion are welded or bonded together, the risk of premature leakage of mercury is relatively low. However, once the seal between body and cap has been broken, the capsule system may not be placed back in the amalgamator for further mixing, which is a significant drawback.
In further detail, despite the fact that a dental practitioner typically has the ability to set both the speed and time of an amalgamator, visual inspection of the particular dental amalgam typically is required in order to determine whether the amalgam alloy and mercury have been sufficiently mixed. If, after having inspected the contents of the mixing chamber, the dental professional determines that the contents have not been adequately mixed, the dental professional may attempt to further mix the contents by hand, which is not a particularly satisfactory option. This subsequent hand mixing consumes valuable working and handling time, which is a significant drawback given that the particular dental amalgam typically sets within five minutes or less. Yet another equally unpalatable option is to begin the process all over again with a new capsule system. However, this method wastes not only time, but materials as well. Moreover, it still does not eliminate the possibility that the contents of the mixing chamber will require further mixing after the seal of the new capsule has been irreversibly broken, and the contents inspected.
The invention overcomes the above-mentioned drawbacks by providing a capsule kit having a first capsule member and a second capsule member, in which the first capsule member has a peripheral end wall, and the second capsule member has a corresponding peripheral recess capable of forming a secure, releasable, resealable seal between the first and second capsule members, thereby enabling a dental professional to open the capsule, inspect the contents of the mixing chamber, and, if necessary, reseal the capsule, and place it back in the amalgamator for continued mixing.
In further detail, the first capsule member has an exterior surface, an interior surface, an opening, an interior space and a first end, with the first end having the peripheral end wall. The peripheral end wall includes a width, an inner edge, an outer edge, and a surface which inclines in the direction of the outer edge. The second capsule member has an exterior surface, an interior surface, an opening, an interior space, and a first end, with the interior surface including the peripheral recess which forms the releasable, yet resealable, seal with the peripheral end wall. When the peripheral end wall and the peripheral recess are positioned together to form the seal, the first and second capsule member openings communicate with each other, and the first and second capsule member interior spaces form a mixing chamber.
In another aspect of the invention, the peripheral end wall has a non-contacting portion which is adjacent the inner edge, with the non-contacting portion being in non-contacting relationship with the peripheral recess when the peripheral end wall and the peripheral recess form a seal. In a further aspect, the peripheral recess includes an upper wall having a projecting end which projects toward a central, longitudinal axis of the second capsule member. The distance between the projecting end and the central, longitudinal axis is greater than the distance between the first capsule member end wall inner edge and the central, longitudinal axis, when the peripheral end wall and the peripheral recess form a releasable seal.
In yet another aspect of the invention, the peripheral recess includes an upper wall having a length, with the length of the peripheral end wall being greater than the length of the peripheral recess upper wall. In a further aspect, the peripheral end wall surface which inclines in the direction of the outer edge is substantially planar, and the peripheral recess has an upper wall which also is substantially planar.
In another aspect, the peripheral end wall has a receivable portion which is received by the peripheral recess. The receivable portion includes the peripheral end wall outer edge, an adjacent inner surface, an adjacent outer surface, and a cross-sectional shape having a first angle formed between the adjacent inner surface and the adjacent outer surface. The peripheral recess includes a base, an adjacent upper wall, an adjacent sidewall, and a cross-sectional shape having a second angle formed between the adjacent upper wall and the adjacent sidewall, with the first angle being greater than the second angle. In addition, if desired, the peripheral recess may be made such that it is more flexible than the receivable portion. In this fashion, although the angle of the peripheral recess may be smaller than the angle of the receivable portion, the added flexibility gives the peripheral recess a bit of a spring action, assisting it in biasing against the receivable portion, thereby improving the integrity of the seal.
In yet another aspect of the invention, the first capsule member further includes a peripheral flange which extends from the exterior surface. This peripheral flange has a cross-sectional diameter which increases in the direction of the first end of the first capsule member. If desired, the peripheral flange may have a sidewall which is substantially planar. In addition, if desired, the peripheral flange may have an upper ledge.
In another aspect, the first capsule member includes a peripheral flange extending from the exterior surface, and the second capsule member includes a peripheral, generally V-shaped indentation along the interior surface, with the indentation having a first sidewall. This peripheral, generally V-shaped indentation is capable of releasably engaging the peripheral flange. If desired, the inner diameter of the second capsule member, along the indentation first sidewall, may decrease in the direction of the first end of the second capsule member. Also, if desired, the outer diameter of the peripheral flange may decrease in the direction away from the first end of the first capsule member, with this decrease being at a rate substantially similar to a rate of decrease of the inner diameter of the second capsule member, along the indentation first sidewall, in the direction of the first end of the second capsule member.
The peripheral flange and the peripheral, generally V-shaped indentation discussed briefly above provide a dental practitioner with an easy-to-use, snap-fit securing system. In this fashion, a dental professional knows that the first and second capsule members are releasably secured together by feeling the snap-like aspect of this feature. Also, the peripheral flange and peripheral, generally V-shaped indentation are designed so that a user easily may separate the first capsule member from the second capsule member. In addition, these aspects of the invention are designed to ensure that a tight, releasable, resealable, seal is formed between the peripheral end wall and the peripheral recess of the first capsule member and second capsule member, respectively.